Request: moving pretrained_models to git submodule

[jamesbraza]

I don't have a ton of storage left on my computer. Cloning this repo takes up almost 892-MB (nearly 1-GB).

Any thoughts on moving pretrained_models, the biggest subfolder = 355-MB, to a git submodule? That way git clone is both much faster and takes up less local storage.

For reference, I am coming here to work with chess. There is no pretrained_models subfolder for chess, so the pretrained_models being readily available after git clone doesn't provide value.